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Formation and emplacement ages of the SSZ-type Neotethyan ophiolites in Central Anatolia, Turkey: palaeotectonic implications

2000-04-01
Yaliniz, MK
Göncüoğlu, Mehmet Cemal
Altıner, Sevinç
Isolated outcrops of ophiolitic rocks, termed the Central Anatolian Ophiolites, are found as allochthonous bodies in the Central Anatolian Crystalline Complex, that represent the metamorphosed passive northern edge of the Tauride-Anatolide Platform, central Turkey. In terms of pseudostratigraphic relationships of the magmatic units and their chemical designation, the Central Anatolian Ophiolites exhibit a supra-subduction zone (fore-arc) setting within the Vardar-Izmir-Ankara-Erzincan segment of the Neotethys. The epi-ophiolitic sedimentary cover of the Central Anatolian Ophiolites is generally characterized by epiclastic volcanogenic deep-sea sediments and debris flows intercalated with pelagic units. The richest and most significant planktonic foraminiferal association recorded from the lowest pelagic members infer a formation age of early-middle 'Turonian to early Santonian. K/Ar ages of post-collisional granitoids (81-65 Ma) intruding the basement rocks as well as the Central Anatolian Ophiolites suggest a post-early Santonian to pre-middle Campanian emplacement age. The marked high volume of epiclastic volcanogenic sediments intercalated with the pelagics of the Central Anatolian Ophiolite is suggestive of rifting in a marginal sea adjacent to a volcanic are. Penecontemporaneous tectonism is reflected in repetitions in the stratigraphy and in debris flows, which result from major slides and mass-gravity reworking of pre-existing units and of are-derived volcanics and sediments.